1. Field of the Invention
The subject matter of the present application relates to electrical fuses, and more specifically to a fuse structure, circuit, and method of programming an electrical fuse having a structure similar to or the same as a MOSFET of an integrated circuit, particularly a MOSFET according to advanced CMOS technology.
2. Description of the Related Art
Fuses have been widely used in integrated circuits to store permanent information on board such as the Electronic Chip Identification (ECID), key system boot code and other critical information in the form of One-Time Programmable Read Only Memory (OTPROM). They are also widely used for redundancy repairs in memories and various integrated circuits to improve manufacturing yield or circuit trimming to fine tune device performance in analog products.
Various types of electrically-blowable fuses have been proposed and used in microelectronic elements, i.e., semiconductor wafers, or portions thereof such as semiconductor chips incorporating integrated circuits. Such fuses are programmed, i.e., blown, from a conductive state to a nonconductive state by driving a programming current through a metal feature which is the fusible element of the fuse that is typically a metallic silicide such as TiSi, CoSi, NiSi, etc. During programming, the current flowing through the metal fusible element of the fuse heats the fusible element either very fast to a critical temperature at which it violently melts or vaporizes (rupture), or through a slower controlled electromigration (EM) process to move metal elements downstream in a direction of movement of electrons therein, and thus create a physical gap in the fusible element, e.g., a discontinuity of the conducting metallic silicide. Whether rupture or EM is the dominant mechanism, the fusible element breaks into two electrically isolated parts, leaving the fusible element in a state much less conductive than before applying the excessive current.
While these types of fuse are ubiquitous today in every imaginable electronic product or equipment, there are limitations to their application under many circumstances. For example, the large size of the fuse itself and support circuitry and its relative high cost can limit the number of fuses used in a given product. The availability of a fuse structure that will work in a given process technology is not always guaranteed. As a result, each process technology can require additional process complexity and costs to establish an adequate fuse solution.
Further improvements can be made to the structure and operation of fuses to be incorporated in integrated circuit devices such as semiconductor chips.